The aim of this project is to examine age-specific changes in biomarkers and age-specific onset of physiological dysregulation across a range of countries with varying epidemiological, economic, behavioral and cultural conditions. We will also link demographic, social, and behavioral factors to the onset of risk across countries including the U.S., England, Taiwan, Mexico, and Indonesia. The data used in this project include the following nationally representative samples that have been harmonized as appropriate for cross-country comparisons: the Health and Retirement Study (HRS) for 2006 and 2010, the English Longitudinal Study of Ageing (ELSA) for 2004 and 2008, the Social Environment and Biomarkers of Aging Study (SEBAS) for 2000 and 2006, the Mexican Family Life Survey (MxFLS) for 2002, 2006, and 2009, and the Indonesia Family Life Survey (IFLS) for 2000 and 2007-8. Recent collection of multiple waves of biomarker data in many areas of the world provides an unparalleled opportunity to systematically and comprehensively study age-specific onset of physiological change, as well as prevalence of risk for a variety of health outcomes, at the national level in countries with varying health histories, health behaviors, and social, cultural and health system characteristics.